Sack ladder



Oci. 21, 1924.

M. TROY SACK LADDER Filer; Nov. 5. 1921 2 Sheetsn Oct. 21, 1924. 1,512,654

- M.TROY

SACK LADDER Filed Nov. 5 1921 2 Sheecs-Sheet 2 a 2%2 a 2355? a u a Patented Oct. 21, 1924.

,UNITED STATES PATENT OFFICE.

. S.ACK LADDER.

Application filed November T0 aZZ whom 2'25 may concern:

Be it knoWn that I, MATTHEW TROT. a citizen of the United States, and a resident of the city of Portland county of Multno1nah. and State of Oregon, have invented a new and useful Improvement in aSack Ladder, of which the foliowing is a specification.

n loading a ship with sacked 1naterial, for exarnple flour, prior to my invention it was common to employ a chute or similar device clown which the sacks were permitted to slide. But the speed at which the sacks descended caused them to impact With such force against any obstruction in their path that they frequently burst. To avoid this, a stevedore was stationed to stop or check the speed of the sack before striking snch obstruction. To eliminate the need of such stevedore a chute or so-called sack ladder was invented as shown by U. S. patent granted to F. W. Brink, No. 707,297. August 19, 1902, for an improvement in chute for loadin, wheat or flour on ships. But such sack ladder was inpracticable, he cause of the abrupt variations in the angles which the planes of the surfaces along which the sacks slid made with each other, requiring the body of the sack to assume sudden changes in form, and thus having;

imposed upon the material of which th sacks were made such strains as requently to cause the sacks to burst when diverted from one step to another.

In other words when the sack had slid down one step its body Would have to a.- sume a sharp curve the instant it is diverted to the ncxt step; but its momentuin Wold be so great that it couid not assume the re quired curved form at the instance et impact with the surface diverting it to the next step, and in consequence the saclz would tend to burst.

I discovered that such bursting of the sacks could be avoided by changing the relative angle of the consecntive planes of the surfaces over which the sacks glide. In short, I discovered that the planes of said surfaces should be so arranged as to make obtuse angles with each other; in that way eliminating all abrupt, extreme changes in the form of the sacks, and per mitting them gradually to change. from one form of curvature to another.

Furthermore, I have discovered that the interior shofld not have any projections ex- 3, 1921. Serial No. 512,472.

tending upwardly from the wails, because the sacks are apt to strike such projections and to he injured and burst hy so doing.

I attain 1ny ohject by the device iliustrated in the accompanying drawi1igs in which Fig. 1 is a perspective of my sack ladder, in this instance comprising only a single section. and the representation in this figure assuming that my sack ladder is Suspended ro1n coaming of the upper deck in position for discharging into the hold of the vessel.

Figs. 2 and 2 are vertical sections of my sack ladder, in this instance showing the same as made of 3 sections which are sepa rated for convenience of handling and storing.

F 3 shows a vertical section of my sack ladder Which, in this instance, is illustrated as composed of only one section; it is assmncd that (lie sack ladder is suspended by similar 1neans as shown in Fig. 1, and this view illustrates the construction of the interior, and the 1nanner in which the sack passes over the stps in descending the 1 a dder.

Fig. 41- is a vertical section looking in the direction pointed by the arrow 4; in Fig. 3, and Fig. is a cross section on the line 5 --5 o;t Fig. 3.

My sack holder comprises a rectangular casing a which when constructed of woo l. may be 1nadc of exterior pieces arranged crosswise, and interior piece 0 arranged vertically; ont any construction Wl!ll sufiicc whieh Will tend to otfer a sniooth surface and little resistance to the passage of the sache.

On the exterior of the casing T provided eyes (E and 6 for fixing suspended cables 0.1 ohains as 7 and h represents the coan1 ing of the upper dock. A chute i in part supported on a horse y' discharges into the upper end of my sack ladder. The upperend is preferably provided with fiaring sides providing a sort of hopper top.

On the interior of the casing a I provided a plurality of steps Z and Z which may consist of angle irons m and suitable flooring secured on these angle irons or merely flanged plates.

The steps project from the interior of the opposite walls of the casing. The steps are downvvardly inclined tovvard each other as more clearly shown in Figs. 2 and 3; and the onde of the steps overlap slightly and are spaced from the opposite wall so as to provide a passageway for the sacks as illustrated in Fig. 3.

It is to be noted that the lower ends of the stops are spaced from the opposite side wall and frorn the top of the next loWer stop relatively to the length and thickness of the sack, in order that the latter Will be cansed to bear oontinuously.on the stops and opposite wall surfaces, suocessively, in passing; and by t-heae means the speed O' motion et the sack is constantly restrained by the incidental friction between the sac]: surfaces and the surfaces ox er which it travels.

As mentioned, I prefer to make my sack ladder in sections, so that the length thereof may be adjused to circumstances. For exarnple, refe rring to Fig. 2 the upper section a inay be made .of a lngth so as to pass the sack fiom the upper dock to the intermediate dock; this top section a being suspendfrom the ooaming of the upper deck; and the intermediate section a niay be suspended from the coaming of the intermediate dock,- or from the upper section, and carries the sack into the lower section 0;, and throngh the latter into the liold of the vesse1. 7

W hen my sack laddor is made in sections these sections must lie s0 proportioned with respect to length and location of the stops in the connected ends of the chute as to adapt tlie latter stops t0 function as described.

A defleotor chute 0 is suspended adjacent: to the lower stop Z' and this deflect0r chute 0 in tnrn discharges on a longer chute 2).

In order to support the upper end of the deflector chute 0, I provide a pair 03. arms q having interOr projecting pins 7*, on Which to bang the hook irons s provided on the underside of the chute o.

I provide snitaole hand holes t under the stops so that any sack which 1night becon1e lodged can be loosened and removed Withont loosening the rigging.

I have experimented with my gravity conveyor in the conductinn of standard grain saoks and flonr sacks in the 3 standard sizes, 50 lbs, 100 lbs. and 140 lbs, and standard sugar sacks, and have constrncted mycasing 25" in width and length with the stps Z 18" wide and the full length across of 25". These extend at approximatey 45 from the side of the casing and wiil overlap the center line 1'.

As is shown in Fig. 2, the distance ma1ked or the distance downward ho tween the ending of the uppcr stop to the beginning of the lower stop is 14'. Thcso distances I have found, transmit the correct wavedike motion of the sack when descending the ladder.

Besides it is to be noted iro1n Figs. 2 and 3 that if the plane of an upper stop were extended so as to intersoct the plane et 111e adjacent opposite wall, and a si1nilarly in terseeting lino wero drawu paralle] with said plane, spaced the1efrom to represenl the thickneSs of the sack, the intersections Would occur soins distance abovo (lie plane of the next lower stop projecting fron1 said wall; and the said intersecting planes wonld make an obtuse angle with cach othcr. In that way the desired affects described in the introduction of the specifieation are cansed.

The illustrations and description abow g;ien are merely intended to show a practt cal mode of construction of my device. Tlie particular details of construction abow descrihed are, however, variable to suit thc ideas of manufacture providi11g such variation retains the essential tmtnres of my invention.

I daim:

A sack ladder comprising an elongato casing o:t rectangular cross section, a series of inclined stops projectim;- alternatcly :t'ro1n opposite walls of: the casing and me tending part way across the space soparat ing said walls, said stops being se relatirol v arranged that the plane m the tread ol an upper stop, if extending to the opposite \\:!ii. wonld intersect the latter sonne distance above the point from which the ncxt lowcr stop projects from such wall. thereby providing a Wall surface abmo said point against which the sack Wlli ho projected from the overlying stop and along which it Will glide to said next lower stop, and thus permitting the sack gradually to change IOD1 one for1n to another in desccndnn the ladder.

MATTHEW TROY. 

